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(11) | EP 0 560 077 A3 |
| (12) | EUROPEAN PATENT APPLICATION |
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| (54) | Multichip module substrate and method of manufacture thereof |
| (57) In accordance with the present invention, an MCM substrate product is manufactured
in an additive process using multiple layers of a fluoropolymer composite material
and copper. The copper layers are plated, and the fluoropolymer composite layers are
laminated. A seeding process promotes reliable bonding between the fluoropolymer composite
material and the plated copper. The use of the filled fluoropolymeric composite eliminates
the need for a barrier metal layer between the insulation and the conductors. The
MCM substrate device of the present invention may have multiple metal layer and multiple
dielectric layers; four or five, or more, of each in a single structure would be easily
achieved and is typical. The structure would include lead lines in separate mutually
orthogonal planes (sometimes referred to as "x" and "y" lead lines) (84, 67) sandwiched
between ground and power voltage planes of copper. The MCM substrate device of the
present invention also has solid copper vias (20, 22), which may be used either as
electrical interconnection between layers of the MCM substrate and/or to the I/C's
to be packaged in the module, or as thermal vias (67, 67a) for heat conduction for
thermal management. The manufacturing process of the present invention makes it possible
to start or stop any via in any layer of the device. Further in accordance with the
present invention, the uppermost layer of the MCM substrate structure (on which the
I/C's would be mounted) may be rigidized to improve wire bonding and handling capabilities
and characteristics of the MCM substrate structure. The rigidized upper layer is in
place of a fluoropolymer layer; and preferably the rigidized upper layer is a cyanate
ester/silica layer. |